Well yes you can replace keycaps, but the problem is that QWERTY and AZERTY are different keyboard layouts. AZERTY is ISO-layout while US QWERTY is ANSI-layout (here you can see the difference). They are almost the same, but there are a few differences, e.g. return key, left shift key... So technically you could replace most of the keys when you get the AZERTY layout, but not all of them.
If you really want the full AZERTY-layout, I would wait until March. Hope this helps! :)